Noninvasive Assessment of Regional and Global Myocardial Contractility in Normal Control Subjects and in Patients with Dilated Cardiomyopathies.

ABSTRACT

The aim of the present study was to develop a new noninvasive approach for the assessment of regional and global myocardial contractility without the need for pharmacological intervention to alter load. Thirty-four healthy adults and five adults with dilated cardiomyopathy (DCM) were studied. Patients with diabetes mellitus and hyperthyroidism were eliminated from the study. The remainder underwent echocardiography, sphygmomanometric blood pressure determination, and carotid pulse tracings. Left ventricular cross section in the parasternal long-axis four- and two-chamber views was divided into 20 segments. Associated measurements of end-systolic pressure and left ventricular ejection time enabled shortening, shortening rate, and ejection fraction/afterload relationships to be determined. A discriminant analysis showed that the ejection fraction/afterload relationship in patients with DCM differed substantially from that of control subjects and was the most sensitive in this regard. Endocardial shortening, mid-wall shortening, and ejection fraction/afterload relationships demonstrated linearity or nonlinearity for control subjects. This study thus permits the assessment of contractility in individual subjects without the need for drug interventions because load alteration stems from the variation of wall stress from base to apex in the left ventricle. More importantly, the approach may be applied to patients with segmental abnormalities of contractile function.